Compared with the traditional technology of setting the touch panel on the liquid crystal panel, the research of unifying the touch panel function and the liquid crystal panel has gradually popular. Then, the embedded touch screen appears. The embedded touch screen comprises two types of in-cell and on-cell. The in-cell touch screen is the technology that the touch control circuit is integrated into the liquid crystal pixels. The on-cell touch screen is the technology that the touch control circuit is integrated between the color filter and the polarizer. Compared with the on-cell touch screen, the in-cell touch screen can make the panel to be thinner.
In the in-cell touch screen technology, the self-capacitance touch control detection skill is generally utilized for detecting the coordinates of the touch control point. The principle is to manufacture a plurality of sensing electrodes on the glass surface with ITO. These sensing electrodes respectively construct capacitances with the ground. The capacitances are self-capacitances, i.e. the capacitances of the sensing electrodes to the ground. When a finger touches the screen, the capacitance of the finger will overlay on the self-capacitance to increase the electric capacity of the self-capacitance. Therefore, the position of the touch control point can be detected by measuring the electric capacity variation of the capacitance of the sensing electrode to the ground.
Each sensing electrode is connected to the touch control IC via one touch control line to realize the scan to the sensing electrode by the touch control IC. Accordingly, the measurement of the electric capacity variation of the self-capacitance can be realized to achieve the touch control operations. However, disconnection or short can easily happen to each sensing electrode and results in being unable to achieve the touch control operations. Therefore, there is a need to provide a circuit capable of performing detection to the sensing electrode fault